Swift's three instruments work together to glean as much information about each burst as possible. Swift's multiwavelength observations of GRBs and afterglow are completely simultaneous. The X-ray Telescope (XRT) and Ultraviolet/Optical Telescope (UVOT) have co-aligned fields-of-view, both within the Burst Alert Telescope (BAT) field-of-view, so that any source can be observed in all three wavebands.

When a GRB occurs, the BAT will be the first of Swift's instruments to detect it. Within about 10 seconds of the burst trigger, the BAT produces a burst localization, which is transmitted to ground observers. In addition, the BAT's position is fed to the Swift spacecraft so a slew can be performed, bringing the GRB into the XRT and UVOT's fields-of-view.

Image to left: Swift's three scientific instruments work together to learn as much as possible about gamma-ray bursts. Credit: NASA/GSFC

Within a minute after a burst, the XRT refines the BAT position. The UVOT produces an even-more accurate localization after about 200 seconds. Meanwhile, the BAT obtains a picture of how the gamma-ray emission evolves over time. X-ray spectra are available after about 20 minutes, and the UVOT filters complete their cycles after about 2 hours. Together, these observations provide a clear picture of the GRB and its afterglow over time in three distinct wavebands.

While not engaged in observations of a new GRB, Swift's telescopes perform preprogrammed observations, which include long-term follow-up of GRBs as well as other science.

Swift and Other Telescopes

Past and current advances in the understanding of gamma-ray bursts (GRBs) have come from the cooperation of many telescopes observing different wavebands. While Swift has the capability of making multiwavelength observations of GRBs, continued multiwavelength observations of GRBs by other telescopes is not only anticipated but is invaluable.

Swift facilitates community-wide contributions to GRB science in two ways. First, Swift disseminates GRB positions as soon as they are available. This allows operators of other satellite and ground-based telescopes to schedule immediate observations when feasible. Second, if a GRB is discovered by another telescope, the coordinates can be uploaded to Swift so that it can perform rapid observations of these bursts.